A. The nominative plural of the five declensions is characterized by the follwing terminations:—

Substantives and adjectives of the first declension have the nominative in ae, and the genitive ārum; as mēnsae, mēnsārum;, bonae, bonārum.

Masculines (and feminines) of the second declension form their plural in ī, neuters in a. The genitive of both is ōrum. E. g. dominī, dominōrum; puerī puerōrum; fīla, fīlōrum; bonī, neut. bona, bonōrum.

Masculines and feminines of the third declension change is of the genitive singular into ēs, neuters, into a and ia. The genitive of this declension is um, or ium. E. g., lapidis, pl. lapidēs, lapidum;vestis, pl. vestis, vestium; pistōris, pl. pistōrēs, pistōrum; capitis, pl. capita, capitum; turpis, pl. turpēs, neut. turpia, gen. turpium.

Masculines and feminines of the fourth declension retain the ūs of the genitive singular, and neuters (in ū) assume the termination ua. The genitive plural of this declension is uniformly uum. E. g. frūctūs, frūctuum; cornua, cornuum.

Nouns of the fifth declension form their plural in ēs, and their genitive ērum; as rēs, rērum; diēs, diērum.

The following list exhibits the nominative and genitive plural of the majority of substantives thus far used in this book, according to the respective declensions:—

The normal termination for the Nom., Acc., and Voc. pl. of neuters is a. Some, however, have always ia. They are:
a) Those ending in e, al, ar, as maria, salia, calcāria, from mare, the sea, sāl, salt, and calcar, a spur;
b) All participles in ns and such adjectives as have either ī or else e or ī in the ablative singular, comparatives excepted, as amantia, ēsurientia, pāria, facilia, turpia from amāns, ēsuriēns, pār, facile, turpe. But we say mājora, doctiōra, from the comp. mājor, greater, doctior, more learned.

The general termination of the genitive plural is um; but the following have ium:—
a) All those which have ia in the nominative plural, as marium, calcārium, amantium, facilium, turpium.
b) Words in ēs and is which do not increase in the genitive singular (i.e. which receive no additional syllable), as nāvis, nāvium; vestis, vestium; nūbēs, nūbium; except vātēs, struēs, canis, pānis, and juvenis, which have vātum, struum, canum, &c.
c) Of nouns in er some have ium, as imber, imbrium; linter, lintrium; venter, ventrium; ūter, ūtrium; others again have um, as patrum, mātrum, frātrum, accipitrum, from pater, māter, &c.—Caro has carnium and senex, senum.
d) Many monosyllables, especially those ending in s and x with a consonant preceding; as dēns, dentium; mōns, montium; merx, mercium; līs, lītium; os, ossium; nox, noctium; vīs, vīrium, &c.
e) Dissylables and polysyllables in ns and rs have generally ium and sometimes um; cohors, cohortium; cliēns, clientium; adolēscēns, adolēscentium; sapiēns, sapientium; but parentēs, parentium.

In the dative and ablative plural, Greek nouns in ma have usually is, sometimes however ibus; as poëma, poëmatis or poëmatibus; diploma, diplomatis or diplomatibus, &c.

The accusative plural of those verbs which have ium in the genitive is among some writers īs or eis, instead of ēs; as artīs, cīvīs, omnīs, instead of artēs, cīvēs, &c.

Remark 1. Some nouns of the fourth declension have ubus instead of ibus in the dat. and abl. pl.; as arcus, arcubus; verū, verubus, &c. Remark 2. The plural of the fifth declension is regular throughout.

The plural of adjectives is subject to the same laws as that of substantives. Thos in us, a, um, and er, ra, rum, follow the inflection of the first and second declensions, and the rest that of the third. Examples:—

Remark.—The general rule is that all adjectives of the third declension have ia in the neuter plural and ium in the genitive.—Like dēformēs are inflected vīlēs, turpēs, and all adjectives in is, e; Like ācrēs, all those ending in er, ris, re.

Remark.—Adjectives of one termination, including participles in ns, generally have ia in the neuter plural and ium in the genitive. Some, however, have a instead of ia in the nominative and accusative, as vetera, plūra, and comparatives generally; e.g. fēlīciōra, mājōra, &c.—Exceptions to the genitive in ium are:

such as have e only in the abl. sing., as pauperum, superstitum;

compounds of faciō and capio, or of such nouns as have um in the gen. pl., as ancipitum, inopum, quadrupedum, &c.;

2 This form of the dative and ablative is the best for dea and fīlia, in order to distinguish them from the same cases of deus and fīlius of the second declension. So the words anima, the soul; līberta, a freed-woman; nāta, daughter; mūla, a she-mule; equa, a mare; asina, a she-ass.—may have ābus instead of īs, and for the same reason. The numerals duo, two, and ambō, both, have duābus and ambābus regularly.

3 So also fabrum, socium, decemvirum, instead of fabrōrum, &c. This contracted genitive (commonly but incorrectly printed um) is the common form of names of measures, weights, and coins, nummum, sēstertium, dēnārium, cadum, medimnum, modium, jūgerum, talentum, the regular genitive plural of nummus, sēsterius, &c. The poets extend this form to names of nations, and say Argīvum, Danaum, &c., in lieu of Argīvōrum, &c.

4 Of the nouns in ē, ās, ēs of this declension no examples have as yet been given. They are mostly of Greek origin, and will be considered hereafter.

5 Of this there is also an ancient form in āī, as aulāī, for aulae, from aula, a hall. But this is not used except in poetry.

6 When a noun is in the plural, sunt, there are, must take the place of the singular est.